We bought a Remington 700 SPS recently and took it out to the range. A lot of fun. Anyways we got some PMC rounds (I think, black and red box) as well as some CBC's. The CBC's were labeled 7,62 X 51 mm NATO. The black and red box was more expensive at $20 for 20 and the CBC's were $40 for 50. When we got to the range, both fired fine, however, the CBC's were very hard to eject. Almost every shot we used, we ended up having to set the gun facing up with its stock on the bench and hit the bolt to get it open. The marksmanship instructor at the range showed us how to do it and told us that the brass was too wide or thick and that was why it would get caught in the 700, and to use higher grade or even match ammo.